Planar substrate edge contact with open volume equalization pathways and side containment

ABSTRACT

A pedestal for a substrate processing system includes a pedestal body including a substrate-facing surface. An annular band is arranged on the substrate-facing surface that is configured to support a radially outer edge of the substrate. A cavity is defined in the substrate-facing surface of the pedestal body and is located radially inside of the annular band. The cavity creates a volume between a bottom surface of the substrate and the substrate-facing surface of the pedestal body. A plurality of vents pass through the pedestal body and are in fluid communication with the cavity to equalize pressure on opposing faces of the substrate during processing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/414,072, filed on Oct. 28, 2016. The entire disclosure of theapplication referenced above is incorporated herein by reference.

FIELD

The present disclosure relates to substrate processing systems, and moreparticularly to pedestals for substrate processing systems.

BACKGROUND

The background description provided here is for the purpose of generallypresenting the context of the disclosure. Work of the presently namedinventors, to the extent it is described in this background section, aswell as aspects of the description that may not otherwise qualify asprior art at the time of filing, are neither expressly nor impliedlyadmitted as prior art against the present disclosure.

Substrate processing systems may be used to deposit, etch or treat filmon a substrate such as a semiconductor wafer. The substrate processingsystems typically include a processing chamber, a gas distributiondevice and a pedestal. During processing, the substrate is arranged onthe pedestal. Different gas mixtures may be introduced into theprocessing chamber to treat the film. Substrate heating and/or radiofrequency (RF) plasma may also be used to activate chemical reactions.

A carrier ring of the pedestal typically contacts the substrate in anarrow band along a radially outer edge of the substrate. Typically, thenarrow band has a width of 1.0 to 1.5 mm. Minimum contact area (MCA)pins are used to support a center region of the substrate. The MCA pinsat the center of the substrate lift the center of the substrate higherthan the narrow band supporting an outer edge of the substrate to createa substrate bowing condition. In other words, top surfaces of the MCApins are raised higher than a planar surface defined by the narrow band.The substrate edge contacts the carrier ring with tangent line or linecontact. This requires precise alignment of the substrate and thepedestal during delivery and processing. Due to the precision requiredand the limits of ‘on-site’ setup, the pins and the carrier ring do nottypically block deposition on a back side of the substrate sufficiently.Since the amount of contact with the backside edge of the substrate isalso limited, this approach is also less tolerant with respect tooff-center substrate placement.

SUMMARY

A pedestal for a substrate processing system includes a pedestal bodyincluding a substrate-facing surface. An annular band that is arrangedon the substrate-facing surface is configured to support a radiallyouter edge of the substrate. A cavity is defined in the substrate-facingsurface of the pedestal body and is located radially inside of theannular band. The cavity creates a volume between a bottom surface ofthe substrate and the substrate-facing surface of the pedestal body. Aplurality of vents pass through the pedestal body and are in fluidcommunication with the cavity to equalize pressure on opposing faces ofthe substrate during processing.

In other features, the band has a width in a range from 4 mm to 12 mm.The band has a width in a range from 5 mm to 9 mm. The band has a widthin a range from 6 mm to 7 mm. The band has a surface roughness (Ra) in arange from 2 to 32. The surface roughness (Ra) in a range from 2 to 24.The surface roughness (Ra) in a range from 2 to 16.

In other features, the plurality of vents include a first vent portionextending radially inwardly from a radially outer side of the pedestalbody and a second vent portion extending from a radially inner edge ofthe first vent portion to the cavity.

In other features, the plurality of vents include a first vent portionextending axially from a bottom side of the pedestal body towards thecavity and a second vent portion including a plurality of holesconnecting the first vent portion to the cavity.

In other features, the band is made of a material selected from a groupconsisting of a dielectric coating formed on a surface of a conductivematerial, an uncoated conductive material, an uncoated metal, and anuncoated dielectric material.

In other features, a ring is arranged radially outside of the substrateand the band. A top surface of the ring is arranged above a top surfaceof the substrate. The ring is made of a dielectric material.

In other features, the dielectric material is selected from a groupconsisting of alumina, aluminum nitride, sapphire, quartz, and siliconoxide. A ring includes a radially inner surface arranged radially insideof and below the substrate and a radially outer surface arrangedradially outside of the substrate. A top surface of the ring is parallelto a top surface of the substrate. The ring is made of a dielectricmaterial.

In other features, the dielectric material is selected from a groupconsisting of alumina, aluminum nitride, sapphire, quartz, and siliconoxide. The pedestal body includes an annular notch around a radiallyouter edge thereof. A ring is arranged in the annular notch. A bottomsurface of the ring lies below a bottom surface of the substrate. A topsurface of the ring lies below a top surface of the substrate. The ringis made of a dielectric material.

In other features, the dielectric material is selected from a groupconsisting of alumina, aluminum nitride, sapphire, quartz, and siliconoxide.

In other features, a plurality of pins is arranged in the cavity tosupport a center of the substrate. A top surface of the pins is one ofbelow, parallel to or above a top surface of the annular band duringprocessing.

In other features, a plurality of projections supports a center of thesubstrate. A top surface of the projections is one of below, parallel toor above a top surface of the annular band. A backside surface of thesubstrate along the radially outer edge of the substrate is parallel tothe band during processing.

A substrate processing system includes a processing chamber and thepedestal. The pedestal is arranged in the processing chamber. An RFgenerator is arranged in the processing chamber.

In other features, a plurality of minimum contact area (MCA) pinsextends from the pedestal body. A controller is configured to extend theMCA pins during processing such that a top surface of the MCA pins isone of below, parallel to or above the band.

In other features, a plurality of projections extends upwardly from thepedestal body in the cavity.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of an example of a substrateprocessing system including a pedestal according to the presentdisclosure;

FIG. 2 is a side cross-sectional view of an example a pedestal accordingto the present disclosure;

FIG. 3 is a perspective view of an example a pedestal according to thepresent disclosure;

FIGS. 4-5 are graphs illustrating back side deposition thickness for anarrow band according to the prior art and for a wider band according tothe present disclosure, respectively;

FIG. 6 is a perspective view of an example of a pedestal includingradial vents to a cavity under the substrate according to the presentdisclosure;

FIG. 7 is a perspective view of an example of a pedestal including axialvents to the cavity under the substrate according to the presentdisclosure;

FIG. 8 is a graph illustrating samples of changes in position of asubstrate during processing with venting according to the presentdisclosure and without venting according to the prior art;

FIG. 9 is a perspective view of an example of a ring including a topsurface located above a top surface of a substrate according to thepresent disclosure;

FIG. 10 is a perspective view of an example of a ring including a topsurface located parallel to a top surface of a substrate according tothe present disclosure; and

FIG. 11 is a perspective view of an example of a ring including a topsurface located below a top surface of a substrate according to thepresent disclosure.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DETAILED DESCRIPTION

A pedestal according to the present disclosure includes an annular bandthat faces upwardly and that supports a radially outer edge of thesubstrate during processing. The annular band has a significantly largerwidth as compared to the narrow band described above. An outer diameterof the substrate along the backside surface of the substrate is kept inparallel or tangential contact with the annular band.

An upper surface of the pedestal defines a cavity between a bottomsurface of the substrate and the upper surface of the pedestal. Thecavity is arranged radially inside of the annular band. Vents areprovided to allow gas to flow from a main processing volume of aprocessing chamber to a volume of the cavity under the substrate. Insome examples, MCA pins are used to support the center of the substrate.In other examples, a plurality of fixed projections extends from theupper surface of the pedestal in the cavity to support the center of thesubstrate.

A ring of dielectric material may be arranged radially outside of theannular band. A radially inner portion of the ring may be locatedradially inside of, adjacent to or radially outside of an outer diameterof the substrate. A top surface of the ring may be located above,parallel to or below a top surface of the substrate.

The annular band of the pedestal according to the present disclosureprovides a wider contact area at the edge of the backside of thesubstrate, which increases the substrate position tolerance. The ventsprovide pressure equalization between the volume in the cavity and themain processing volume. The vents can be radially directed to an outerdiameter of the pedestal or axially directed from a bottom of thepedestal. The number of vents and the size of vent passages will varydepending on the process pressure and gas flows that are used in aparticular process.

The width of the annular band varies depending on the processtemperatures and chemistries used to deposit film on the substrate. Thegeometry and location of the ring varies relative to the substratediameter and the pedestal to tune process variables for a particularfilm to be deposited. The thickness, volume and shape of the ring may bevaried depending on the process variables for a particular film to bedeposited.

Referring now to FIG. 1, an example of a substrate processing system forperforming deposition described herein is shown. While specific examplesof substrate processing systems are shown, other substrate processingsystems can be used. In some examples, the substrate processing systemperforms plasma enhanced (PE) deposition of film. In some examples, thesubstrate processing system performs plasma-enhanced chemical vapordeposition (PECVD) or plasma-enhanced atomic layer deposition (PEALD),although other processes can be performed.

A substrate processing system 10 includes a processing chamber 12 thatencloses other components of the substrate processing system 10 andcontains the RF plasma (if used for a particular substrate treatment).The substrate processing system 10 includes a showerhead 14 and apedestal assembly 16. A substrate 18 is arranged on the pedestalassembly 16. The showerhead 14 introduces and distributes process gases.

If plasma is used, the plasma can be direct or remote plasma. In thisexample, an RF generating system 30 generates and outputs an RF voltageto either the showerhead 14 or the pedestal assembly 16 (the other is DCgrounded, AC grounded or floating). For example only, the RF generatingsystem 30 may include an RF voltage generator 32 that generates the RFvoltage that is fed by a matching network 34 to the showerhead 14 or thepedestal assembly 16. Alternately, the plasma may be delivered by aremote plasma source 36.

A gas delivery system 40 includes one or more gas sources 42-1, 42-2, .. . , and 42-N (collectively gas sources 42), where N is an integergreater than zero. The gas sources 42 supply one or more etch gasmixtures, precursor gas mixtures, cleaning gas mixtures, ashing gasmixtures, etc. to the processing chamber 12. Vaporized precursor mayalso be used. The gas sources 42 are connected by valves 44-1, 44-2, . .. , and 44-N (collectively valves 44) and mass flow controllers 46-1,46-2, . . . , and 46-N (collectively mass flow controllers 46) to amanifold 48. An output of the manifold 48 is fed to the processingchamber 12. For example only, the output of the manifold 48 is fed tothe showerhead 14.

A heater 50 may be connected to a heater coil (not shown) arranged inthe pedestal assembly 16. The heater 50 may be used to control atemperature of the pedestal assembly 16 and the substrate 18. A valve 60and pump 62 may be used to evacuate reactants from the processingchamber 12. A controller 70 may be used to control components of thesubstrate processing system 10. For example only, the controller 70 maybe used to control flow of process gases, monitoring of processparameters such as temperature, pressure, power, etc, striking andextinguishing plasma, removal of reactants, etc.

In some examples, minimum contact area (MCA) pins 71 are used to supporta center region of the substrate 18 during processing. If used, thecontroller 70 may also be used to actuate the MCA pins 71. In someexamples, a top surface of the MCA pins 71 are positioned at a heightthat is below, parallel to or above a top surface of the annular band toprovide parallel contact between the substrate and the annular band. Insome examples, the MCA pins 71 are made of sapphire, although othermaterials can be used. The MCA pins 71 can be set such that the heightis above, parallel, or below the annular band in order to modify thecontact force between the substrate (wafer) and the annular ring (sealband). Higher contact force can ensure reduced backside deposition onthe substrate by reducing the gap between substrate and annular ring.There are limits on both how far above and below the MCA pins 71 can beto the annular ring; in both directions, going too far reduces thecontact force between substrate and ring thereby increasing gap.

Referring now to FIGS. 2-3, the pedestal assembly 16 includes a pedestalbody 110 that supports the substrate 18. A cavity 118 may be definedbetween the substrate 18 and a top surface 119 of the pedestal body 110.In some examples, the cavity 118 has a cylindrical shape. An annularband 122 is arranged radially outside of the cavity 118. In someexamples, the annular band 122 is planar and includes a radially inneredge 126 and a radially outer edge 128. The outer diameter of thesubstrate 18 is kept in parallel or tangential contact with the annularband 122 during processing. A ring 132 is arranged on the pedestal body110 generally radially outside of the substrate 18.

In some examples, the annular band 122 has a surface roughness R_(a) of2-32. In some examples, the annular band 122 has a surface roughnessR_(a) of 2-24. In some examples, the annular band 122 has a surfaceroughness R_(a) of 2-16. In some examples, the annular band 122 has asurface roughness R_(a) of 2-8.

A radial width of the annular band 122 is selected to be sufficientlywide enough to ensure that the substrate edge remains in contactregardless of the substrate placement. In some examples, the annularband 122 has a radial width in a range from 4 mm to 12 mm. In someexamples, the annular band 122 has a radial width in a range from 5 mmto 9 mm. In some examples, the annular band 122 has a radial width in arange from 6 mm to 7 mm.

A material that forms the annular band 122 may include a dielectriccoating formed on a surface of a conductive material, an uncoatedconductive material or metal, or an uncoated dielectric material. Thematerial used for the annular band 122 may be selected so that it doesnot chemically interact with process chemistries that are used todeposit the film. Additional criteria for selection include impedanceand plasma interaction. In some examples, the material used for theannular band 122 may also be selected to provide a specific interactionwith some process chemistries.

Referring now to FIGS. 4-5, the impact of a width of the annular band122 on back side deposition is shown. As can be seen, when the annularband 122 has a narrow width as described above, backside depositiontends to occur as shown in FIG. 4. When the annular band 122 has a widerwidth as disclosed herein, back side deposition is reduced or eliminatedas shown in FIG. 5.

Referring now to FIGS. 6-7, several different variations are shown forventing the volume in the cavity 118 to provide pressure equalizationwith the main processing volume. The venting provides pressureequalization between opposing surfaces of the substrate 18 to reducemovement of the substrate 18 on the annular band 122. The reducedmovement tends to improve deposition uniformity and to prevent back sidedeposition.

For example in FIG. 6, the pedestal body 110 includes a plurality ofvents 150-1, 150-2, 150-3, . . . 150-V (collectively vents 150) (where Vis an integer greater than or equal to one). As can be appreciated, thenumber of vents can be adjusted as needed to provide suitable dynamicpressure equalization. The vents 150 provide fluid communication betweenthe main processing volume and the volume in the cavity 118 below thesubstrate 18. In this example, the vents 150 include a first ventportion 152-1 extending in a radial direction and including an opening154-1 located on a radially outer surface of the pedestal body 110. Asecond vent portion 156-1 extends in an axial direction from a radiallyinner end 158-1 of the first vent portion 152-1 to an upper surface ofthe pedestal body 110 in the cavity 118. The first vent portion 152-1and the second vent portion 156-1 provide a path for fluid communicationbetween the volume under the substrate (in the cavity 118) and the mainprocessing volume in which processing occurs. In other words, pressureequalization occurs because the main volume of the processing chamberincludes the top surface of the substrate 18 and the vents 150 providepressure equalization in the volume of the cavity 118 below thesubstrate 18 to prevent substrate movement.

A height of the cavity 118 under the substrate 18 is selected to allowthe exchange of gases into and from the cavity 118 without creating anupward pressure on the substrate 18 that is large enough to cause thesubstrate 18 to move within predetermined limits. In some examples, thecavity 118 has a depth in the range from 0.004″ to 0.010″. In someexamples, the cavity has a depth in the range from 0.004″ to 0.008″. Aplurality of MCA pins 161 may be used to support and lift a center ofthe substrate 18. In some examples, the MCA pins 161 are moved to aheight where a top surface of the MCA pins 161 are parallel to a topsurface of the annular band 122. In some examples, the MCA pins 161 aremoved to a height where a top surface of the MCA pins 161 are above atop surface of the annular band 122. In some examples, the MCA pins 161may include three or six MCA pins, although additional or fewer MCA pinscan be used.

In FIG. 7, another example of a vent arrangement is shown. A pluralityof vents 200-1 and 200-2 (collectively vents 200) are arranged in anaxial direction to vent fluid from the main processing volume to thecavity 118 arranged below the substrate 18. As can be appreciated, whiletwo vents are shown, additional vents may be arranged radially aroundthe pedestal body 110 at spaced intervals. In some examples, the vent200-1 includes a first vent portion 210-1 extending from a bottomsurface of the pedestal body 110, through one or more layers of thepedestal body 110 to (or a location near but spaced from) a top surfaceof the pedestal in the cavity 118. A second vent portion 210-2optionally connects the first vent portion 210-1 to the cavity 118. Insome examples, each of the second vent portions 210-2 includes aplurality of spaced through holes 220 having opposite ends in fluidcommunication with the first vent portion 210-1 and the cavity 118,respectively.

In some examples, the first vent portions 210-1 have a diameter in arange from 0.2″ to 0.8″. In some examples, the first vent portions 210-1have a diameter in a range from 0.3″ to 0.5″. In some examples, theplurality of spaced through holes 220 are approximately an order ofmagnitude smaller than the first vent portion 210-1. In some examples,the plurality of spaced through holes 220 have a diameter in a rangefrom 0.01″ to 0.08″. In some examples, the plurality of spaced throughholes 220 have a diameter in a range from 0.01″ to 0.03″.

Referring now to FIG. 8, a plurality of substrates are delivered to aprocess, treated and then retrieved. The substrates are initiallydelivered near a (0,0) point and are subsequently picked up by a robotarm after processing. As can be appreciated, the pickup location of therobot arm provides an indication of how much the substrate moved duringprocessing. When the pedestal body is not vented, the substrates tend tomove on the top surface of the pedestal body due to a pressuredifferential between the main processing volume and the volume in thecavity 118. In contrast, the substrate moves less when venting is used.As the substrate moves relative to the ring, localized differences indeposition may occur. When there is decreased movement of the substrate18, there is less variation in deposition.

Referring now to FIGS. 9-11, various example arrangements for the ring132 are shown. The ring 132 has a generally annular shape and can bemade of a dielectric material. In some examples, the dielectric materialis selected from alumina, aluminum nitride, sapphire, quartz, andsilicon oxide. In FIG. 9, the ring 132-1 is arranged radially outside anouter diameter (OD) of the substrate and the annular band 122. The ring132-1 includes a lower portion 313 that is received in a notch 315 ofthe pedestal body 110. The ring 132-1 further includes an upper portion317. In some examples, the upper portion 317 of the ring 132-1 has alarger radial thickness as compared to the lower portion 313. The ring132-1 includes a radially inner surface 300-1 that is spaced radiallyoutside of the outer edge 128 of the annular band 122 and the radiallyouter edge of the substrate 18. A top surface 310-1 of the ring 132-1 islocated above, parallel to or below a top surface of the substrate 18.

In FIG. 10, the ring 132-2 includes a first annular notch 330 that atleast partially lies underneath a radially outer edge of the substrate18. The first annular notch 330 is arranged radially inside of an outerdiameter of the substrate 18 and radially outside of the annular band122. The ring 132-2 further includes a radially innermost surface 334that is spaced radially inside of the radially outer edge of thesubstrate 18. A radially inner top surface 332 of the ring 132-2provides relief to accommodate the radially outer edge of the substrate18. A top surface 310-2 of the ring 132-2 is located below, above orparallel to a top surface of the substrate 18. In some examples, the topsurface 310-2 lies in a plane that is parallel to a plane including thetop surface of the substrate 18.

In FIG. 11, the pedestal body 110 includes an annular recess 340arranged around a radially outer edge of the pedestal body 110. A ring132-3 has an annular shape and includes a lower portion 342 having anaxial height d2 that is greater than an axial height d1 of the annularrecess 340. A top surface 350 of the ring 132-3 is arranged in a planethat is parallel to a top surface of the substrate 18 or above or belowa top surface of the substrate 18 by a distance d3.

The ring 132 modifies an ionization rate and electron density adjacentto an edge of the substrate 18. The ring 132 lowers the occurrence ofunwanted plasma discontinuities in this area. The ring 132 alsophysically constrains movement of the substrate 18 on the pedestal body110. The ring 132 reduces plasmoids that may occur at the edge of thesubstrate 18 when using some gas species, the band and/or venting. Theproximity of the ring 132 at the outer diameter of the substrate 18 canreduce the electron density and ionization rates near the edge of thesubstrate.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. It should be understood thatone or more steps within a method may be executed in different order (orconcurrently) without altering the principles of the present disclosure.Further, although each of the embodiments is described above as havingcertain features, any one or more of those features described withrespect to any embodiment of the disclosure can be implemented in and/orcombined with features of any of the other embodiments, even if thatcombination is not explicitly described. In other words, the describedembodiments are not mutually exclusive, and permutations of one or moreembodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example,between modules, circuit elements, semiconductor layers, etc.) aredescribed using various terms, including “connected,” “engaged,”“coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and“disposed.” Unless explicitly described as being “direct,” when arelationship between first and second elements is described in the abovedisclosure, that relationship can be a direct relationship where noother intervening elements are present between the first and secondelements, but can also be an indirect relationship where one or moreintervening elements are present (either spatially or functionally)between the first and second elements. As used herein, the phrase atleast one of A, B, and C should be construed to mean a logical (A OR BOR C), using a non-exclusive logical OR, and should not be construed tomean “at least one of A, at least one of B, and at least one of C.”

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a substrate pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor substrate or substrate. The electronics may be referred toas the “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, substrate transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor substrate or to a system. Theoperational parameters may, in some embodiments, be part of a recipedefined by process engineers to accomplish one or more processing stepsduring the fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of asubstrate.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with the system, coupled to the system,otherwise networked to the system, or a combination thereof. Forexample, the controller may be in the “cloud” or all or a part of a fabhost computer system, which can allow for remote access of the substrateprocessing. The computer may enable remote access to the system tomonitor current progress of fabrication operations, examine a history ofpast fabrication operations, examine trends or performance metrics froma plurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor substrates.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of substrates to and fromtool locations and/or load ports in a semiconductor manufacturingfactory.

What is claimed is:
 1. A pedestal for a substrate processing system,comprising: a pedestal body including a substrate-facing surface and anannular notch around a radially outer edge thereof; an annular bandarranged on the substrate-facing surface that is configured to support aradially outer edge of a substrate; and a cavity that is defined in thesubstrate-facing surface of the pedestal body and that is locatedradially inside of the annular band, wherein the cavity creates a volumebetween a bottom surface of the substrate and the substrate-facingsurface of the pedestal body; a plurality of vents passing through thepedestal body and in fluid communication with the cavity to equalizepressure on opposing faces of the substrate during processing, whereinthe plurality of vents each include: a first vent portion extendingradially inwardly from a radially outer side of the pedestal body; and asecond vent portion extending perpendicularly from a radially inner edgeof the first vent portion to the cavity; and a ring that is separatefrom the pedestal body and that is arranged in the annular notch on thepedestal body, wherein a bottom surface of the ring lies below a bottomsurface of the substrate, wherein a top surface of the ring lies below atop surface of the substrate, and wherein the ring is made of adielectric material.
 2. The pedestal of claim 1, wherein the annularband has a width in a range from 4 mm to 12 mm.
 3. The pedestal of claim1, wherein the annular band has a width in a range from 5 mm to 9 mm. 4.The pedestal of claim 1, wherein the annular band has a width in a rangefrom 6 mm to 7 mm.
 5. The pedestal of claim 1, wherein the annular bandhas a surface roughness (Ra) in a range from 2 to
 32. 6. The pedestal ofclaim 5, wherein the surface roughness (Ra) in a range from 2 to
 24. 7.The pedestal of claim 5, wherein the surface roughness (Ra) in a rangefrom 2 to
 16. 8. The pedestal of claim 1, wherein the annular band ismade of a material selected from a group consisting of a dielectriccoating formed on a surface of a conductive material, an uncoatedconductive material, an uncoated metal, and an uncoated dielectricmaterial.
 9. The pedestal of claim 1, wherein the dielectric material isselected from a group consisting of alumina, aluminum nitride, sapphire,quartz, and silicon oxide.
 10. The pedestal of claim 1, furthercomprising: a plurality of pins arranged in the cavity to support acenter of the substrate, wherein a top surface of the pins is one ofbelow, parallel to or above a top surface of the annular band duringprocessing.
 11. The pedestal of claim 1, further comprising: a pluralityof projections to support a center of the substrate, wherein a topsurface of the projections is one of below, parallel to or above a topsurface of the annular band.
 12. The pedestal of claim 1, wherein theannular band is configured to support a backside surface of thesubstrate along the radially outer edge such that the substrate isparallel to the annular band during processing.
 13. The pedestal ofclaim 1, further comprising a plurality of projections extendingupwardly from the pedestal body in the cavity.
 14. A pedestal for asubstrate processing system, comprising: a pedestal body including asubstrate-facing surface; an annular band arranged on thesubstrate-facing surface that is configured to support a radially outeredge of a substrate; and a cavity that is defined in thesubstrate-facing surface of the pedestal body and that is locatedradially inside of the annular band, wherein the cavity creates a volumebetween a bottom surface of the substrate and the substrate-facingsurface of the pedestal body; a plurality of vents passing through thepedestal body and in fluid communication with the cavity to equalizepressure on opposing faces of the substrate during processing, whereinthe plurality of vents each include: a first vent portion extendingradially inwardly from a radially outer side of the pedestal body; and asecond vent portion extending perpendicularly from a radially inner edgeof the first vent portion to the cavity; and a ring that is separatefrom the pedestal body and that is arranged radially outside of thesubstrate and the annular band on the pedestal body, wherein a topsurface of the ring is arranged above a top surface of the substrate,and wherein the ring is made of a dielectric material.
 15. The pedestalof claim 14, wherein the dielectric material is selected from a groupconsisting of alumina, aluminum nitride, sapphire, quartz, and siliconoxide.
 16. A pedestal for a substrate processing system, comprising: apedestal body including a substrate-facing surface an annular bandarranged on the substrate-facing surface that is configured to support aradially outer edge of a substrate; and a cavity that is defined in thesubstrate-facing surface of the pedestal body and that is locatedradially inside of the annular band, wherein the cavity creates a volumebetween a bottom surface of the substrate and the substrate-facinqsurface of the pedestal body; a plurality of vents passing through thepedestal body and in fluid communication with the cavity to equalizepressure on opposing faces of the substrate during processing, whereinthe plurality of vents each include: a first vent portion extendingradially inwardly from a radially outer side of the pedestal body; and asecond vent portion extending perpendicularly from a radially inner edgeof the first vent portion to the cavity; and a ring that is separatefrom the pedestal body, that is arranged on the pedestal body, and thatincludes a radially inner surface arranged radially inside of and belowthe substrate and a radially outer surface arranged radially outside ofthe substrate, wherein a top surface of the ring is parallel to a topsurface of the substrate, and wherein the ring is made of a dielectricmaterial.
 17. The pedestal of claim 16, wherein the dielectric materialis selected from a group consisting of alumina, aluminum nitride,sapphire, quartz, and silicon oxide.
 18. A substrate processing systemcomprising: a processing chamber; the pedestal of claim 1, wherein thepedestal is arranged in the processing chamber; and an RF generatorarranged in the processing chamber.
 19. The substrate processing systemof claim 18, further comprising: a plurality of minimum contact area(MCA) pins extendable from the pedestal body; and a controllerconfigured to extend the MCA pins during processing such that a topsurface of the MCA pins is one of below, parallel to or above theannular band.